Protective cover assemblies having a frame and a material covering the frame are well known for protecting spaces such as boats, wagons, trailers, as well as the cargo area of a pick-up truck. The frame typically includes a plurality of rails disposed about the perimeter of the space for supporting the material. A variety of methods to secure and tighten the material over the space have been employed over the years.
In the past, the protective cover was attached directly to the walls defining the space. Although effective, this method is not preferred due to the fact that a plurality of holes needed to be drilled into the walls defining the space to attach one side of a snap assembly. The holes cause permanent disfigurement to the appearance of the walls defining the space. The holes invite an opportunity for corrosion thus causing further deterioration to the appearance and functionality of the walls. Additionally, there was no adjustment available to account for dimensional changes in the material due to wear or temperature.
In recent years, improvements have been made in an attempt to improve the fit of protective covers to accommodate dimensional variations of the material due to environmental changes including the use of frames having tensioning devices and the use of various methods of attaching material to the frames. An example of such improvement is disclosed in U.S. Pat. No. 6,293,608 to Dicke et al. (the '608 patent).
The '608 patent discloses a protective cover assembly including a front rail and a rear rail spaced from the front rail and further including a pair of side rails spaced from each other and substantially perpendicular to the front and rear rails. A plurality of corner pieces couple the rails together. A pair of self-adjusting devices interconnect the rear rail to the side rails. Each of the self-adjusting devices include a stop coupled to the side rails, a biasing device disposed between the stop and the corner piece, and an interconnecting plate fixedly coupled to the side rail and slidably coupled to the corner piece for accommodating relative movement between the rear rail and the side rails.
Although the prior art protective covers teach various methods of accommodating dimensional changes in the material, there remains an opportunity for a tensioner having a simple design using few parts and not requiring adjustment.